IP Library › Granted Patent US 8,992,343
Granted Patent B2
US 8,992,343 · App. 14/220,180 · Granted Mar 31, 2015

Multi-layer cover golf ball having thermoset rubber intermediate cover layer

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Quick Facts
Patent No.
US 8,992,343
App. No.
14/220,180
Filed
Mar 20, 2014
Granted
Mar 31, 2015
Kind
B2
Art Unit
3711
USPC
473/370
Abstract

A golf ball including a core and a cover including a thermoplastic inner cover layer having a material hardness of 60 to 80 Shore D; a thermoset outer cover layer comprising a castable polyurea and having a material hardness of 20 to 60 Shore D; and a thermoset intermediate cover layer disposed between the inner and outer cover layers and having a hardness substantially the same as the inner cover layer hardness and greater than the outer cover layer hardness. The inner cover includes one or more high- or low-acid ionomers and, optionally, a maleic anhydride modified polyolefin. The intermediate layer is formed from a castable liquid polybutadiene rubber.

Claims (16)

1. A golf ball comprising a core and a three-layer cover, the cover comprising:

a thermoplastic inner cover layer disposed about the core and having a material hardness of about 60 Shore D to about 80 Shore D;

a thermoplastic polyurethane outer cover layer having a material hardness of about 20 Shore D to about 60 Shore D; and

a thermoset intermediate cover layer disposed between the inner and outer cover layers and having a hardness substantially the same as the inner cover layer hardness and greater than the outer cover layer hardness;

wherein the inner cover layer comprises one or more low-acid ionomers and the intermediate cover layer is formed from an ethylene propylene diene monomer-based liquid rubber polymer having a viscosity of about 10,000 cp or less.

2. The golf ball of claim 1 , wherein the inner cover layer comprise a blend of Li and Na low-acid ionomers.

3. The golf ball of claim 1 , wherein the outer cover layer is cast or reaction injection molded.

4. The golf ball of claim 1 , wherein the liquid rubber composition comprises about 30% to about 70% solids at a submersion time of about 10 sec to about 60 sec.

5. The golf ball of claim 1 , wherein the liquid rubber composition, when in a solid state, can be extended under ambient conditions at least twice its resting length, and upon stress release can return to within 15% of its original length.

6. The golf ball of claim 1 , wherein the liquid rubber composition further comprises a crosslinking agent comprising one or more metallic salts of a carboxylic acid.

7. The golf ball of claim 1 , wherein the viscosity is about 1,000 cp or less.

8. The golf ball of claim 1 , wherein the liquid rubber composition is vulcanized with peroxide or sulfur cure accelerators.

9. The golf ball of claim 1 , wherein the ethylene propylene diene monomer-based liquid rubber polymer comprises ethylidene norborene diene monomer or dicyclopentadiene.

10. The golf ball of claim 1 , wherein a combination of the inner cover, the intermediate cover, and the outer cover have a total thickness of 0.125 inches or less.

11. The golf ball of claim 10 , wherein the total thickness is 0.115 inches or less.

12. The golf ball of claim 1 , wherein the outer cover layer is cast or reaction injection molded.